feat(ci) use a more future-proof way of installing Node in CI

Install the version based on .nvmrc rather than speficying it in the
action.

.github/workflows/ci.yml

@@ -10,8 +10,12 @@ jobs:
     - uses: actions/checkout@v4
     - uses: actions/setup-node@v4
       with:
-        node-version: 20
+        node-version-file: '.nvmrc'
         cache: 'npm'
+    - name: Check Node / npm versions
+      run: |
+        node -v
+        npm -v
     - name: Get changed files
       id: changed-files
       uses: tj-actions/changed-files@v41
@@ -37,8 +41,12 @@ jobs:
     - uses: actions/checkout@v4
     - uses: actions/setup-node@v4
       with:
-        node-version: 20
+        node-version-file: '.nvmrc'
         cache: 'npm'
+    - name: Check Node / npm versions
+      run: |
+        node -v
+        npm -v
     - run: npm install
     - run: make
   macos-ci:
@@ -59,8 +67,12 @@ jobs:
     - uses: actions/checkout@v4
     - uses: actions/setup-node@v4
       with:
-        node-version: 20
+        node-version-file: '.nvmrc'
         cache: 'npm'
+    - name: Check Node / npm versions
+      run: |
+        node -v
+        npm -v
     - run: npm install
     - run: npx react-native bundle --entry-file react/index.native.js --platform android --bundle-output /tmp/android.bundle --reset-cache
   ios-build:
@@ -74,8 +86,12 @@ jobs:
     - uses: actions/checkout@v4
     - uses: actions/setup-node@v4
       with:
-        node-version: 20
+        node-version-file: '.nvmrc'
         cache: 'npm'
+    - name: Check Node / npm versions
+      run: |
+        node -v
+        npm -v
     - run: npm install
     - name: setup Xcode
       run: |
@@ -102,8 +118,12 @@ jobs:
     - uses: actions/checkout@v4
     - uses: actions/setup-node@v4
       with:
-        node-version: 16
+        node-version-file: '.nvmrc'
         cache: 'npm'
+    - name: Check Node / npm versions
+      run: |
+        node -v
+        npm -v
     - run: npm install
     - run: make
     - run: sudo apt-get install -y debhelper